git1...I LOVE the water hyacinth in Missouri....here in Missouri, it poses very little danger and loads of summer benefits in a pond! In warmer climates it is or can indeed be considered highly invasive!

In a one acre pond, too much coverage is very easily removed manually if needed. I used loops of 1/2" cheap black plastic tubing made into "rings" using a single splice to keep them in certain areas of my pond.